In automotive fuel supply pipes, an elastic sealing ring is fitted into the connector that connects one piping component to another piping component, so that this elastic sealing ring prevents the fuel from leaking between one piping component and another piping component.
In recent years, permeation of automotive fuel from the piping system is being regulated more strictly, and it is anticipated that these regulations will become increasingly stringent in the future.
Accordingly, not only must the elastic sealing ring prevent leakage of the fuel from the fuel supply piping, but it must have excellent impermeability to the fuel, i.e., low permeability is required.
An elastic sealing ring is mounted in the connection joint to connect the fuel supply hose to a rigid companion pipe. The elastic sealing ring forms a seal between the connection joint and the companion pipe. The sealing ring must provide excellent impermeability to the fuel, i.e. low permeability is required.
However, if the sealing material is impermeable to fuel (for example fluoro rubber or fluororesin) but has poor low-temperature performance, there may be a problem with poor sealing ability due to a loss of elastic strength at low temperatures.
Heretofore, the countermeasure has been to use an elastic sealing ring that has excellent low temperature properties in addition to an elastic sealing ring that has low permeability, and the use of an elastic sealing ring that has excellent low temperature properties in combination with an elastic sealing ring that has low permeability has been suggested.
For example, as disclosed in Japanese Unexamined Patent Application Publication (Kokai) No. 2003-287180 a piping connection joint (quick connector) is described in which an elastic sealing ring that has low permeability is combined together with an elastic sealing ring that has excellent low temperature properties.
A concrete example of the above is shown in FIG. 8.
In this example Figure, 200 is a quick connector connection joint, and 202 is the connector body that forms the main body
Connector body 202 has a tubular shape, with a retainer holding component 204 at one end in the axial direction, hose connector component 206 at the other end, and a housing 208 in the middle.
Component 210 is a retainer that is held in a fixed position along the axial direction separated from a retainer holding component 204 which engages a ring-shaped protruding engagement flange component 213 at its interior peripheral edge fro providing support to companion pipe 212 to prevent it from falling out of the housing 208.
A pair of elastic sealing rings 214, 216 are mounted inside housing component 208, and are in a state of elastic contact with the exterior peripheral surface of companion pipe 212 to form a seal between housing 208 and companion pipe 212, i.e., between quick-connect 200 and companion pipe 212.
Furthermore, 218 is a bushing mounted in housing 208 against the exterior peripheral surface of companion pipe 212.
Elastic sealing ring 214 is formed from a fluoro rubber material that has a low permeability toward fuel. In other words, elastic sealing ring 214 is a low permeability elastic sealing ring.
One of the elastic sealing rings 216 is formed from a low temperature-resistant material of, for example, NBR (nitrile rubber) with excellent low temperature performance that maintains high elasticity at low temperatures. In other words, elastic sealing ring 216 is an elastic sealing ring with excellent low temperature performance (low temperature resistance).
Low permeability elastic sealing ring 214 is formed from a low permeability material such as fluoro rubber and the like, and loses its elastic power as it hardens at low temperature, and when vehicle body vibrations increase, the favorable compliant deformation with respect to the relative positions of companion pipe 212 and housing 208 is lost, and because the sealing ability is diminished, the goal of maintaining the sealability is separated from the excellent low temperature performance in elastic sealing ring 216, in other words it is used in combination with low permeability elastic sealing ring 214.
Thus, in the case which requires a minimum of the 2 elastic rings 214 and 216, the housing 208 must of an appropriate length to accommodate both elastic rings, causing the quick connector 200 to end up being even longer. Stated otherwise there must be sufficient linear space in the axial direction to accommodate the connector component for companion pipe 212 and the fuel transport hose.
Since the space for piping in vehicles is limited, the use of 2 elastic rings is undesirable in the sense of using the space efficiently.
Moreover, when fitting the elastic sealing rings into connector body 202, a much longer fitting time is required to fit two separate elastic sealing rings 214, 216, and produces a fitting problem.